This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Ursodeoxycholic acid (UDCA) is currently the only approved drug for the treatment of PBC. It has been shown to prolong the time to liver transplant and may prolong survival. UDCA does this by reducing the damaging effects of toxic compounds called bile salts that can build up in the liver when there is damage to the ducts. However, UDCA has no effect on the immune system and thus the immune injury to the bile ducts responsible for the disease. Immunosuppressive medications (drugs that lower the immune system), such as methotrexate and tacrolimus, therefore, have been evaluated in clinical trials as treatment for PBC. Even though such studies have shown these drugs to be safe at the dosages prescribed, their potential long-term side effects are unknown. The purpose of this study is to find out if methotrexate or tacrolimus may cause delayed, previously unrecognized effects, either harmful or beneficial, to patients who participated in clinical trials evaluating these medications in PBC at this institution. Subjects will be seen at 3, 6, or 12 month intervals depending upon the severity. This is an observational study.